PORT ST. LUCIE — The Mets have a first-base competition again — sort of.

Even with Ike Davis’ return to the lineup on Thursday and Lucas Duda expected to resume play on Friday, manager Terry Collins admitted he’s unsure what criteria will be used over these final eight days of spring training for selecting a starting first baseman.

“I wish I could tell you how we’re going to do it,” Collins said after the Mets’ 7-6 exhibition victory over the Braves. “Right now it’s probably who is going to be the healthiest.”

So what once held the promise of becoming an old-fashioned spring training position battle has possibly been reduced to, “Which guy is hurt the least?”

Davis, who has battled left- and right-calf soreness, went 0-for-3 and played first base in his initial Grapefruit League action since March 1. Duda, who hasn’t played since March 2 because of left hamstring soreness, is expected to start at first base on Friday against the Twins, with Davis at designated hitter. Both will be taking a 2 ¹/₂-hour bus ride to Fort Myers, Fla., for the game.

By the time the Mets depart Montreal on March 29, after the second of two exhibition games against the Blue Jays, they hope to have the situation resolved. Even so, general manager Sandy Alderson said both players could be on the Opening Day roster.

But Duda said there is no sense of anxiety on his part concerning the final outcome.

“I’m actually looking forward to it — see how it plays out,” Duda said.

Alderson was vague when asked what factors will determine the starting first baseman.

“We have to pay attention over the next [eight] days,” Alderson said. “That’s the amount of time we have and that’s the time we’ll use.”

But he conceded the small window to evaluate both players has changed the nature of the competition.

“I think you have to be a little more cautious, and maybe not do something that has forever implications,” Alderson said.

That would seem to rule out a trade of either player before the season, but Davis or Duda could still begin the year at Triple-A Las Vegas.

Davis said his focus Thursday was just playing in a regular game again instead of minor league exhibitions in which he did not run the bases.

“But actually I felt pretty good in the box today,” Davis said. “I hit a couple of balls hard and obviously didn’t get a hit, but it felt good to get out there and barrel up some balls.”

It will get trickier to get at-bats for Davis and Duda on the same day beyond Sunday’s split squad, because the DH won’t be in play again until the Mets reach Montreal. Collins said he might rotate players over to the minor league complex to get at-bats in the meantime.

Given that he has battled a hamstring injury, Duda is almost certainly not a candidate to see action in the outfield before camp breaks, if ever. The Mets began last year with Duda as their left fielder, but before the season ended it was clear any future he might have with the organization would be as a first baseman.

Davis was just happy to wear a first baseman’s mitt again on Thursday.

“I haven’t played any defense in a game for a month, so that’s the biggest thing, probably getting out there and getting used to the flow of game on defense,” Davis said.

As for having only eight days to prove he deserves the starting first-base job, Davis was succinct.